Transgenic and knockout mouse models have become an integral part ofthe research programs at Salk. The Transgenic Core is dedicated to providing access to cutting-edge technologies to create these models. Core services include microinjection of DNA constructs into one-cell stage embryos, microinjection of gene targeted mouse embryonic stem (ES) cells into blastocysts, lentiviral infection and injection, in-vitro fertilization (IVF), cryopreservation and rederivation of mouse lines. In addition, the Core offers injection of human embryonic stem (hES) cell lines and induced pluripotent stem (IPS) cell lines into immunodeficient mice to form teratomas. The Transgenic Core develops new techniques and applications, provides immediate access to individuals with knowledge of dealing with transgenic mice, and offers the potential for research collaborations. More than 100 publications were based on genetically altered mouse lines created by the Transgenic Core since 1994. All CCSG supported core are organized into one group: Basic Research. This shared resource is categorized as category (1.03) Transgenic Animal Facility in summary ID